Segment Maps

The plugin currently supports US maps. Segement maps take as input 4 columns: start latitude , start longitude, end latitude, and end longitude of the segment. The model and data styles for the subsequent examples are:

explore: airports is table('malloy-data.faa.airports') {
  primary_key: code
  dimension: name is concat(code, ' - ', full_name)
  measure: airport_count is count()
}

explore: flights is table('malloy-data.faa.flights') {
  primary_key: id2
  rename: origin_code is origin
  rename: destination_code is destination

  join_one: origin is airports with origin_code
  join_one: destination is airports with destination_code

  measure: flight_count is count()

  query: routes_map is {
    group_by: [
      origin.latitude
      origin.longitude
      latitude2 is destination.latitude
      longitude2 is destination.longitude
    ]
    aggregate: flight_count
  }
}

and data styles are

{
  "routes_map": {
    "renderer": "segment_map"
  }
}

Run as a simple query

Departing from Chicago

-- Bug: as a main query we only return 50 results, nested we get the whole thing...
-- query: flights{ where: dep_time = @2003-02 and origin.code ='ORD'}->routes_map
query: flights{ where: dep_time = @2003-02 and origin.code ='ORD'}->{nest:routes_map}

routes_map

Run as a trellis

By calling the configured map as a nested query, a trellis is formed.

query: flights{ where: dep_time = @2003-02 and origin.code ='ORD'}->{
  group_by: carrier
  aggregate: flight_count
  nest:routes_map
}

carrier	flight_count	routes_map
UA	9,443
AA	7,255
MQ	4,975
DH	3,906
NW	702

Run as a trellis, repeated with different filters

--! {"isRunnable": true, "runMode": "auto", "source": "/inline/e.malloy", "size": "medium", "dataStyles":{"routes_map": {"renderer": "segment_map"}}}
query: flights->{
  group_by: carrier
  aggregate: flight_count
  nest: [
    ord_segment_map is routes_map {where: origin.code: 'ORD'}
    sfo_segment_map is routes_map {where: origin.code: 'SFO'}
    jfk_segment_map is routes_map {where: origin.code: 'JFK'}
  ]
}

carrier	flight_count	ord_segment_map	sfo_segment_map	jfk_segment_map
WN	5,775,777
DL	4,477,929
AA	4,434,727
UA	3,654,646
US	3,205,810